This invention relates to mode indication and shutter speed indication device in a camera having both an automatic exposure control for both aperture-priority and shutter-speed-priority and a manual exposure control mechanism.
Heretofore, for shutter-speed-priority automatic exposure control, the aperture ring of the lens was set to the minimum aperture value or a position adjacent thereto indicating "automatic aperture and exposure control", a shutter speed value selected by the photographer was set and a stop operation suitable for the shutter speed value thus set was automatically controlled by the camera. On the other hand, for aperture-priority automatic exposure control, the shutter dial was set to the automatic exposure position, an aperture value selected by the photographer was set and a shutter speed suitable for the aperture value thus set was controlled by the camera. In a camera having a single automatic exposure control mechanism as described above, it was possible merely to switch between automatic and manual photographing modes and accordingly there was no opportunity to make a mistake in switching between the photographing modes.
However, in a camera having both a shutter-speed-priority automatic exposure control mechanism and an aperture-priority automatic exposure control mechanism, it is necessary to switch between a shutter-speed-priority automatic exposure mode, an aperture-priority automatic exposure mode and a manual exposure mode. Accordingly, it is necessary for such a camera to provide a photographing mode switching member in addition to an aperture setting ring and a shutter speed setting dial. Thus, the camera suffers from drawbacks in that the photographer may operate the camera erroneously by setting the operating members to improper combinations of position. It is rather difficult for the photographer to instantly detect the presently set photographing mode from the settings of the operating members.
This will become more apparent from FIG. 1 which shows a camera having an aperture setting ring, a shutter speed setting dial 3, and a photographing mode switching member 4. In performing a photographing operation according to the shutter-speed-priority automatic exposure system with the camera shown in FIG. 1, the mode switching member 4 is set to mark "A-AUTO", the aperture ring 2 is set to mark "A", and the shutter dial 3 is set to a desired shutter speed. That is, in this case, three operating members are operated before the photographing operation which is undoubtedly inconvenient in the case where photographing must be achieved quickly. If, in the setting of the above-described operating members, the aperture ring 2 were set to positions other than the mark "A", the setting of the aperture ring would be inconsistent with the settings of the other operating members. It is desirable that this possibility be eliminated. Furthermore, in the case where the aperture ring 2 is set to the mark "A" and the shutter dial 3 is set to mark "B" (bulb), it cannot be readily determined which one of the aperture-priority automatic exposure control and shutter-speed-priority automatic exposure control takes precedence over the other.
In addition, in the case of aperture-priority automatic exposure, it is necessary to set the mode switching member 4 to mark "S-AUTO", the aperture ring 2 to a desired aperture value, and the shutter dial 3 to "automatic". In this case, automatic exposure can be effected independently of the setting of the shutter dial 3. However, when the aperture ring 2 is set to the mark "A", it is not possible to independently set the aperture value. These difficulties in operating the device are due to the fact that the camera has a number of operating members and indicating members.
Accordingly, an object of the invention is to provide a device in which the settings of the above-described operating members are consistent with one another regardless of what settings are employed and the photographer can readily determine the contents of the settings.